How to I get the property belonging to a custom attribute?

Question

I need to find the type of the property that a custom attribute is applied to from within the custom attribute.

For example:

[MyAttribute]
string MyProperty{get;set;}

Given the instance of MyAttribute, how could I get a Type descriptor for MyProperty?

In other words, I am looking for the opposite of System.Type.GetCustomAttributes()

You might be better off saying what you are trying to do, becasue what you are asking isn't possible. — Matthew Whited, May 27 '09 at 17:12

score 21 · Accepted Answer · edited Jun 23 '10 at 06:13

21

The attribute itself knows nothing about the object that was decorated with it. But you could inject this information at the time you retrive the attribute.
At some point you have to retrieve the property using code similar to the following.

PropertyInfo propertyInfo = typeof(MyType).GetProperty("MyProperty");

Object[] attribute = propertyInfo.GetCustomAttributes(typeof(MyAttribute), true);

if (attribute.Length > 0)
{
    MyAttribute myAttribute = (MyAttribute) attributes[0];

    // Inject the type of the property.
    myAttribute.PropertyType = propertyInfo.PropertyType;

    // Or inject the complete property info.
    myAttribute.PropertyInfo = propertyInfo;
}

edited Jun 23 '10 at 06:13

luvieere

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answered May 27 '09 at 17:21

Daniel Brückner

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I needed this for my problem and I found [another solution here](https://stackoverflow.com/questions/4879521/how-to-create-a-custom-attribute-in-c-sharp/44595783#answer-4879579). I elaborated on this and posted a response for accessing a custom attribute on a property and not a class, too. Thank you, by the way! – Hopper Jun 16 '17 at 18:30

score 4 · Answer 2 · answered May 27 '09 at 17:05

4

The custom attribute knows nothing about the attributed element so I don't think what you want is possible to do unless you enumerate all types in your system and check if they contain such attribute.

answered May 27 '09 at 17:05

Otávio Décio

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How to I get the property belonging to a custom attribute?

2 Answers2

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